Of more than 7,000 disasters over the past two decades, in which 1.35 million people died, 90 percent of those deaths occurred in low and middle-income countries. Ban called it "a damning indictment of inequality". Ban said "High-income countries suffer huge economic losses in disasters, but people in low-income countries pay with their lives."

On average the death toll per disaster in low-income countries was five times more than in high-income countries which have more effective early warning systems and better preparedness, according to the Centre for Research on the Epidemiology of Disasters, which collects the data.

The impoverished Caribbean nation of Haiti, which suffered a devastating earthquake in 2010, lost more lives than any other country between 1996 and 2015, said the study. Last week Haiti was struck again when Hurricane Matthew killed at least 1,000 people and left around 1.4 million in urgent need of aid.

Earthquakes and tsunamis were the biggest killers overall in the past 20 years, followed closely by climate-related disasters, which are increasing in number as the planet warms, according to the report.

Ban warned "hundreds of millions of people" are at risk of rising seas, earthquakes, and climate and weather extremes. They live on marginal lands, beneath unstable hillsides or on storm-exposed coastlines," he said. "This is why eradicating extreme poverty ... is essential to reducing disaster risk."

The report said the number of weather and climate-related disasters had more than doubled in the last two decades compared with the preceding two. All nations are being affected, including richer countries that have suffered tens of thousands of deaths linked to heat-waves in particular. But the poorest are still far more likely to die.

The U.N. Office for Disaster Risk Reduction head Robert Glasser, Glasser compared Cyclone Nargis, which hit Myanmar's coast in 2008 resulting in 138,000 deaths, to the zero casualties in Australia when top-strength Cyclone Yasi slammed into Queensland in 2010. "The irony is that those countries that have contributed least to climate change, to this crisis we face, are the ones that are being hit the hardest in terms of loss of life from these events," Glasser told reporters.